tutorial04.c

// tutorial04.c
// A pedagogical video player that will stream through every video frame as fast as it can,
// and play audio (out of sync).
//
// Code based on FFplay, Copyright (c) 2003 Fabrice Bellard,
// and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)
// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
// Use
//
// gcc -o tutorial04 tutorial04.c -lavformat -lavcodec -lz -lm -lswscale`sdl-config --cflags --libs`
// to build (assuming libavformat and libavcodec are correctly installed,
// and assuming you have sdl-config. Please refer to SDL docs for your installation.)
//
// Run using
// tutorial04 myvideofile.mpg
//
// to play the video stream on your screen.



#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>

#include <SDL.h>
#include <SDL_thread.h>

#ifdef __MINGW32__
#undef main /* Prevents SDL from overriding main() */
#endif

#include <stdio.h>
#include <math.h>

#define SDL_AUDIO_BUFFER_SIZE 1024

#define MAX_AUDIOQ_SIZE (5 * 16 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)

#define FF_ALLOC_EVENT   (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)

#define VIDEO_PICTURE_QUEUE_SIZE 1

typedef struct PacketQueue {
    AVPacketList *first_pkt, *last_pkt;
    int nb_packets;
    int size;
    SDL_mutex *mutex;
    SDL_cond *cond;
} PacketQueue;


typedef struct VideoPicture {
    SDL_Overlay *bmp;
    int width, height; /* source height & width */
    int allocated;
} VideoPicture;

typedef struct VideoState {

    AVFormatContext *pFormatCtx;
    int             videoStream, audioStream;
    AVStream        *audio_st;
    PacketQueue     audioq;
    uint8_t         audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2];
    unsigned int    audio_buf_size;
    unsigned int    audio_buf_index;
    AVPacket        audio_pkt;
    uint8_t         *audio_pkt_data;
    int             audio_pkt_size;
    AVStream        *video_st;
    PacketQueue     videoq;

    VideoPicture    pictq[VIDEO_PICTURE_QUEUE_SIZE];
    int             pictq_size, pictq_rindex, pictq_windex;
    SDL_mutex       *pictq_mutex;
    SDL_cond        *pictq_cond;

    SDL_Thread      *parse_tid;
    SDL_Thread      *video_tid;

    char            filename[1024];
    int             quit;
} VideoState;

SDL_Surface     *screen;

/* Since we only have one decoding thread, the Big Struct
   can be global in case we need it. */
VideoState *global_video_state;

void packet_queue_init(PacketQueue *q) {
    memset(q, 0, sizeof(PacketQueue));
    q->mutex = SDL_CreateMutex();
    q->cond = SDL_CreateCond();
}
int packet_queue_put(PacketQueue *q, AVPacket *pkt) {

    AVPacketList *pkt1;
    if(av_dup_packet(pkt) < 0) {
        return -1;
    }
    pkt1 = av_malloc(sizeof(AVPacketList));
    if (!pkt1)
        return -1;
    pkt1->pkt = *pkt;
    pkt1->next = NULL;

    SDL_LockMutex(q->mutex);

    if (!q->last_pkt)
        q->first_pkt = pkt1;
    else
        q->last_pkt->next = pkt1;
    q->last_pkt = pkt1;
    q->nb_packets++;
    q->size += pkt1->pkt.size;
    SDL_CondSignal(q->cond);

    SDL_UnlockMutex(q->mutex);
    return 0;
}
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block)
{
    AVPacketList *pkt1;
    int ret;

    SDL_LockMutex(q->mutex);

    for(;;) {

        if(global_video_state->quit) {
            ret = -1;
            break;
        }

        pkt1 = q->first_pkt;
        if (pkt1) {
            q->first_pkt = pkt1->next;
            if (!q->first_pkt)
                q->last_pkt = NULL;
            q->nb_packets--;
            q->size -= pkt1->pkt.size;
            *pkt = pkt1->pkt;
            av_free(pkt1);
            ret = 1;
            break;
        } else if (!block) {
            ret = 0;
            break;
        } else {
            SDL_CondWait(q->cond, q->mutex);
        }
    }
    SDL_UnlockMutex(q->mutex);
    return ret;
}

int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size) {

    int len1, data_size;
    AVPacket *pkt = &is->audio_pkt;

    for(;;) {
        while(is->audio_pkt_size > 0) {
            data_size = buf_size;
            len1 = avcodec_decode_audio2(is->audio_st->codec,
                                         (int16_t *)audio_buf, &data_size,
                                         is->audio_pkt_data, is->audio_pkt_size);
            if(len1 < 0) {
                /* if error, skip frame */
                is->audio_pkt_size = 0;
                break;
            }
            is->audio_pkt_data += len1;
            is->audio_pkt_size -= len1;
            if(data_size <= 0) {
                /* No data yet, get more frames */
                continue;
            }
            /* We have data, return it and come back for more later */
            return data_size;
        }
        if(pkt->data)
            av_free_packet(pkt);

        if(is->quit) {
            return -1;
        }
        /* next packet */
        if(packet_queue_get(&is->audioq, pkt, 1) < 0) {
            return -1;
        }
        is->audio_pkt_data = pkt->data;
        is->audio_pkt_size = pkt->size;
    }
}

void audio_callback(void *userdata, Uint8 *stream, int len) {

    VideoState *is = (VideoState *)userdata;
    int len1, audio_size;

    while(len > 0) {
        if(is->audio_buf_index >= is->audio_buf_size) {
            /* We have already sent all our data; get more */
            audio_size = audio_decode_frame(is, is->audio_buf, sizeof(is->audio_buf));
            if(audio_size < 0) {
                /* If error, output silence */
                is->audio_buf_size = 1024;
                memset(is->audio_buf, 0, is->audio_buf_size);
            } else {
                is->audio_buf_size = audio_size;
            }
            is->audio_buf_index = 0;
        }
        len1 = is->audio_buf_size - is->audio_buf_index;
        if(len1 > len)
            len1 = len;
        memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
        len -= len1;
        stream += len1;
        is->audio_buf_index += len1;
    }
}

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque) {
    SDL_Event event;
    event.type = FF_REFRESH_EVENT;
    event.user.data1 = opaque;
    SDL_PushEvent(&event);
    return 0; /* 0 means stop timer */
}

/* schedule a video refresh in 'delay' ms */
static void schedule_refresh(VideoState *is, int delay) {
    SDL_AddTimer(delay, sdl_refresh_timer_cb, is);
}

void video_display(VideoState *is) {

    SDL_Rect rect;
    VideoPicture *vp;
    AVPicture pict;
    float aspect_ratio;
    int w, h, x, y;
    int i;

    vp = &is->pictq[is->pictq_rindex];
    if(vp->bmp) {
        if(is->video_st->codec->sample_aspect_ratio.num == 0) {
            aspect_ratio = 0;
        } else {
            aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio) *
                           is->video_st->codec->width / is->video_st->codec->height;
        }
        if(aspect_ratio <= 0.0) {
            aspect_ratio = (float)is->video_st->codec->width /
                           (float)is->video_st->codec->height;
        }
        h = screen->h;
        w = ((int)rint(h * aspect_ratio)) & -3;
        if(w > screen->w) {
            w = screen->w;
            h = ((int)rint(w / aspect_ratio)) & -3;
        }
        x = (screen->w - w) / 2;
        y = (screen->h - h) / 2;

        rect.x = x;
        rect.y = y;
        rect.w = w;
        rect.h = h;
        SDL_DisplayYUVOverlay(vp->bmp, &rect);
    }
}

void video_refresh_timer(void *userdata) {

    VideoState *is = (VideoState *)userdata;
    VideoPicture *vp;

    if(is->video_st) {
        if(is->pictq_size == 0) {
            schedule_refresh(is, 1);
        } else {
            vp = &is->pictq[is->pictq_rindex];
            /* Now, normally here goes a ton of code
            about timing, etc. we're just going to
             guess at a delay for now. You can
             increase and decrease this value and hard code
             the timing - but I don't suggest that ;)
             We'll learn how to do it for real later.
                */
            schedule_refresh(is, 80);

            /* show the picture! */
            video_display(is);

            /* update queue for next picture! */
            if(++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE) {
                is->pictq_rindex = 0;
            }
            SDL_LockMutex(is->pictq_mutex);
            is->pictq_size--;
            SDL_CondSignal(is->pictq_cond);
            SDL_UnlockMutex(is->pictq_mutex);
        }
    } else {
        schedule_refresh(is, 100);
    }
}

void alloc_picture(void *userdata) {

    VideoState *is = (VideoState *)userdata;
    VideoPicture *vp;

    vp = &is->pictq[is->pictq_windex];
    if(vp->bmp) {
        // we already have one make another, bigger/smaller
        SDL_FreeYUVOverlay(vp->bmp);
    }
    // Allocate a place to put our YUV image on that screen
    vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width,
                                   is->video_st->codec->height,
                                   SDL_YV12_OVERLAY,
                                   screen);
    vp->width = is->video_st->codec->width;
    vp->height = is->video_st->codec->height;

    SDL_LockMutex(is->pictq_mutex);
    vp->allocated = 1;
    SDL_CondSignal(is->pictq_cond);
    SDL_UnlockMutex(is->pictq_mutex);

}

int queue_picture(VideoState *is, AVFrame *pFrame) {

    VideoPicture *vp;
    int dst_pix_fmt;
    AVPicture pict;
    static struct SwsContext *img_convert_ctx;

    /* wait until we have space for a new pic */
    SDL_LockMutex(is->pictq_mutex);
    while(is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE &&
            !is->quit) {
        SDL_CondWait(is->pictq_cond, is->pictq_mutex);
    }
    SDL_UnlockMutex(is->pictq_mutex);

    if(is->quit)
        return -1;

    // windex is set to 0 initially
    vp = &is->pictq[is->pictq_windex];

    /* allocate or resize the buffer! */
    if(!vp->bmp ||
            vp->width != is->video_st->codec->width ||
            vp->height != is->video_st->codec->height) {
        SDL_Event event;

        vp->allocated = 0;
        /* we have to do it in the main thread */
        event.type = FF_ALLOC_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);

        /* wait until we have a picture allocated */
        SDL_LockMutex(is->pictq_mutex);
        while(!vp->allocated && !is->quit) {
            SDL_CondWait(is->pictq_cond, is->pictq_mutex);
        }
        SDL_UnlockMutex(is->pictq_mutex);
        if(is->quit) {
            return -1;
        }
    }
    /* We have a place to put our picture on the queue */

    if(vp->bmp) {

        SDL_LockYUVOverlay(vp->bmp);

        dst_pix_fmt = PIX_FMT_YUV420P;
        /* point pict at the queue */

        pict.data[0] = vp->bmp->pixels[0];
        pict.data[1] = vp->bmp->pixels[2];
        pict.data[2] = vp->bmp->pixels[1];

        pict.linesize[0] = vp->bmp->pitches[0];
        pict.linesize[1] = vp->bmp->pitches[2];
        pict.linesize[2] = vp->bmp->pitches[1];

        // Convert the image into YUV format that SDL uses
        /*
        img_convert(&pict, dst_pix_fmt,
        	(AVPicture *)pFrame, is->video_st->codec->pix_fmt,
        	is->video_st->codec->width, is->video_st->codec->height);
        */
        // Convert the image into YUV format that SDL uses
        if(img_convert_ctx == NULL) {
            int w = is->video_st->codec->width;
            int h = is->video_st->codec->height;
            img_convert_ctx = sws_getContext(w, h,
                                             is->video_st->codec->pix_fmt,
                                             w, h, dst_pix_fmt, SWS_BICUBIC,
                                             NULL, NULL, NULL);
            if(img_convert_ctx == NULL) {
                fprintf(stderr, "Cannot initialize the conversion context!\n");
                exit(1);
            }
        }
        sws_scale(img_convert_ctx, pFrame->data,
                  pFrame->linesize, 0,
                  is->video_st->codec->height,
                  pict.data, pict.linesize);

        SDL_UnlockYUVOverlay(vp->bmp);
        /* now we inform our display thread that we have a pic ready */
        if(++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE) {
            is->pictq_windex = 0;
        }
        SDL_LockMutex(is->pictq_mutex);
        is->pictq_size++;
        SDL_UnlockMutex(is->pictq_mutex);
    }
    return 0;
}

int video_thread(void *arg) {
    VideoState *is = (VideoState *)arg;
    AVPacket pkt1, *packet = &pkt1;
    int len1, frameFinished;
    AVFrame *pFrame;

    pFrame = avcodec_alloc_frame();

    for(;;) {
        if(packet_queue_get(&is->videoq, packet, 1) < 0) {
            // means we quit getting packets
            break;
        }
        // Decode video frame
        len1 = avcodec_decode_video(is->video_st->codec, pFrame, &frameFinished,
                                    packet->data, packet->size);

        // Did we get a video frame?
        if(frameFinished) {
            if(queue_picture(is, pFrame) < 0) {
                break;
            }
        }
        av_free_packet(packet);
    }
    av_free(pFrame);
    return 0;
}

int stream_component_open(VideoState *is, int stream_index) {

    AVFormatContext *pFormatCtx = is->pFormatCtx;
    AVCodecContext *codecCtx;
    AVCodec *codec;
    SDL_AudioSpec wanted_spec, spec;

    if(stream_index < 0 || stream_index >= pFormatCtx->nb_streams) {
        return -1;
    }

    // Get a pointer to the codec context for the video stream
    codecCtx = pFormatCtx->streams[stream_index]->codec;

    if(codecCtx->codec_type == CODEC_TYPE_AUDIO) {
        // Set audio settings from codec info
        wanted_spec.freq = codecCtx->sample_rate;
        wanted_spec.format = AUDIO_S16SYS;
        wanted_spec.channels = codecCtx->channels;
        wanted_spec.silence = 0;
        wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
        wanted_spec.callback = audio_callback;
        wanted_spec.userdata = is;

        if(SDL_OpenAudio(&wanted_spec, &spec) < 0) {
            fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
            return -1;
        }
    }
    codec = avcodec_find_decoder(codecCtx->codec_id);
    if(!codec || (avcodec_open(codecCtx, codec) < 0)) {
        fprintf(stderr, "Unsupported codec!\n");
        return -1;
    }

    switch(codecCtx->codec_type) {
    case CODEC_TYPE_AUDIO:
        is->audioStream = stream_index;
        is->audio_st = pFormatCtx->streams[stream_index];
        is->audio_buf_size = 0;
        is->audio_buf_index = 0;
        memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
        packet_queue_init(&is->audioq);
        SDL_PauseAudio(0);
        break;
    case CODEC_TYPE_VIDEO:
        is->videoStream = stream_index;
        is->video_st = pFormatCtx->streams[stream_index];

        packet_queue_init(&is->videoq);
        is->video_tid = SDL_CreateThread(video_thread, is);
        break;
    default:
        break;
    }
}

int decode_interrupt_cb(void) {
    return (global_video_state && global_video_state->quit);
}

int decode_thread(void *arg) {

    VideoState *is = (VideoState *)arg;
    AVFormatContext *pFormatCtx;
    AVPacket pkt1, *packet = &pkt1;

    int video_index = -1;
    int audio_index = -1;
    int i;

    is->videoStream=-1;
    is->audioStream=-1;

    global_video_state = is;
    // will interrupt blocking functions if we quit!
    url_set_interrupt_cb(decode_interrupt_cb);

    // Open video file
    if(av_open_input_file(&pFormatCtx, is->filename, NULL, 0, NULL)!=0)
        return -1; // Couldn't open file

    is->pFormatCtx = pFormatCtx;

    // Retrieve stream information
    if(av_find_stream_info(pFormatCtx)<0)
        return -1; // Couldn't find stream information

    // Dump information about file onto standard error
    dump_format(pFormatCtx, 0, is->filename, 0);

    // Find the first video stream

    for(i=0; i<pFormatCtx->nb_streams; i++) {
        if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO &&
                video_index < 0) {
            video_index=i;
        }
        if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_AUDIO &&
                audio_index < 0) {
            audio_index=i;
        }
    }
    if(audio_index >= 0) {
        stream_component_open(is, audio_index);
    }
    if(video_index >= 0) {
        stream_component_open(is, video_index);
    }

    if(is->videoStream < 0 || is->audioStream < 0) {
        fprintf(stderr, "%s: could not open codecs\n", is->filename);
        goto fail;
    }

    // main decode loop

    for(;;) {
        if(is->quit) {
            break;
        }
        // seek stuff goes here
        if(is->audioq.size > MAX_AUDIOQ_SIZE ||
                is->videoq.size > MAX_VIDEOQ_SIZE) {
            SDL_Delay(10);
            continue;
        }
        if(av_read_frame(is->pFormatCtx, packet) < 0) {
            if(url_ferror(&pFormatCtx->pb) == 0) {
                SDL_Delay(100); /* no error; wait for user input */
                continue;
            } else {
                break;
            }
        }
        // Is this a packet from the video stream?
        if(packet->stream_index == is->videoStream) {
            packet_queue_put(&is->videoq, packet);
        } else if(packet->stream_index == is->audioStream) {
            packet_queue_put(&is->audioq, packet);
        } else {
            av_free_packet(packet);
        }
    }
    /* all done - wait for it */
    while(!is->quit) {
        SDL_Delay(100);
    }

fail:
    if(1) {
        SDL_Event event;
        event.type = FF_QUIT_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);
    }
    return 0;
}

int main(int argc, char *argv[]) {

    SDL_Event       event;

    VideoState      *is;

    is = av_mallocz(sizeof(VideoState));

    if(argc < 2) {
        fprintf(stderr, "Usage: test <file>\n");
        exit(1);
    }
    // Register all formats and codecs
    av_register_all();

    if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
        fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
        exit(1);
    }

    // Make a screen to put our video
#ifndef __DARWIN__
    screen = SDL_SetVideoMode(640, 480, 0, 0);
#else
    screen = SDL_SetVideoMode(640, 480, 24, 0);
#endif
    if(!screen) {
        fprintf(stderr, "SDL: could not set video mode - exiting\n");
        exit(1);
    }

    //pstrcpy(is->filename, sizeof(is->filename), argv[1]);
	av_strlcpy(is->filename, argv[1], sizeof(is->filename));

    is->pictq_mutex = SDL_CreateMutex();
    is->pictq_cond = SDL_CreateCond();

    schedule_refresh(is, 40);

    is->parse_tid = SDL_CreateThread(decode_thread, is);
    if(!is->parse_tid) {
        av_free(is);
        return -1;
    }
    for(;;) {

        SDL_WaitEvent(&event);
        switch(event.type) {
        case FF_QUIT_EVENT:
        case SDL_QUIT:
            is->quit = 1;
            SDL_Quit();
            return 0;
            break;
        case FF_ALLOC_EVENT:
            alloc_picture(event.user.data1);
            break;
        case FF_REFRESH_EVENT:
            video_refresh_timer(event.user.data1);
            break;
        default:
            break;
        }
    }
    return 0;

}